SAR影像与TM影像的几种融合处理方法

利用彩色空间变换、比值变换及相关系数法分别对SAR影像与TM3 、TM4 、TM5 三波段影像进行融合处理。文章介绍了影像融合中的具体技术问题及其处理方法。因侧视雷达图像一般有明显的孤立噪声,所以,在进行影像融合处理之前,先对SAR影像进行预处理,文中用δ滤波法抑制孤立噪声(光斑) .最后,从视觉效果、熵、平均梯度值以及标准差等4 方面评价了影像融合的质量。     

空间数据融合的框架流程及发展现状研究

在介绍空间数据概念和框架流程的基础上,文章将数据集成、数据匹配和数据融合三个重要环节分别展开,列举了各自的内容、处理方法及研究现状。重点介绍了基于本体的语义集成,线状、面状要素的数据匹配,矢量、栅格数据间的融合处理,以及空间数据基础设施(SDI)。     

Fusion of PolSAR and PolInSAR data for land cover classification

The main research goal of this study is to investigate the complementarity and fusion of different frequencies (L- and P-band), polarimetric SAR (PolSAR) and polarimetric interferometric (PolInSAR) data for land cover classification. A large feature set was derived from each of these four modalities and a two-level fusion method was developed: Logistic regression (LR) as ‘feature-level fusion’ and the neural-network (NN) method for higher level fusion. For comparison, a support vector machine (SVM) was also applied. NN and SVM were applied on various combinations of the feature sets.     

Toward reduction of artifacts in fused images

Most fusion satellite image methodologies at pixel-level introduce false spatial details, i.e. artifacts, in the resulting fused images. In many cases, these artifacts appears because image fusion methods do not consider the differences in roughness or textural characteristics between different land covers. They only consider the digital values associated with single pixels. This effect increases as the spatial resolution image increases. To minimize this problem, we propose a new paradigm based on local measurements of the fractal dimension (FD). Fractal dimension maps (FDMs) are generated for each of the source images (panchromatic and each band of the multi-spectral images) with the box-counting algorithm and by applying a windowing process. The average of source image FDMs, previously indexed between 0 and 1, has been used for discrimination of different land covers present in satellite images. This paradigm has been applied through the fusion methodology based on the discrete wavelet transform (DWT), using the à trous algorithm (WAT). Two different scenes registered by optical sensors on board FORMOSAT-2 and IKONOS satellites were used to study the behaviour of the proposed methodology. The implementation of this approach, using the WAT method, allows adapting the fusion process to the roughness and shape of the regions present in the image to be fused. This improves the quality of the fused images and their classification results when compared with the original WAT method.     

一种DLG数据要素融合算法的设计与实现

空间数据生产是分幅进行的,因此,在实际应用中经常需要将跨图幅的面状或线状要素,合并成同一要素,使其符合现实世界情况.从数据生产与应用的角度,提出了一种DLG数据要素融合算法,并基于.net平台使用C#语言对算法进行了实现.实践证明,该算法对DLG数据要素融合是有效的,且算法处理效率较高.     

Partial iterates for symmetrizing non-parametric color correction

Mosaic generation is a central tool in various fields ranging way beyond the scope of photogrammetry and requires the radiometry and color of the images to be corrected. Correction can either be done by a global parametric approach (looking for an optimal gain or gamma for each image of the mosaic), or by iteratively correcting image pairs with a non-parametric approach. Such non-parametric approaches allow for much finer correction but are asymmetric, i.e. they require the choice of a source image that will be corrected to match a target image. Thus the result on the whole mosaic will be very dependant on the order in which images are corrected. In this paper, we propose to use partial iterates to symmetrize non-parametric correction in order to solve this problem. Partial iterates formalize what partially applying a bijective function means and we explain how this can be done in both the continuous and discrete domain. This mechanism is applied to a simple non-parametric approach (histogram transfer of the luminance) to show its potential.     

Earth observation data based rapid flood-extent modelling for tsunami-devastated coastal areas

Earth observation (EO)-based mapping and analysis of natural hazards plays a critical role in various aspects of post-disaster aid management. Spatial very high-resolution Earth observation data provide important information for managing post-tsunami activities on devastated land and monitoring re-cultivation and reconstruction. The automatic and fast use of high-resolution EO data for rapid mapping is, however, complicated by high spectral variability in densely populated urban areas and unpredictable textural and spectral land-surface changes. The present paper presents the results of the SENDAI project, which developed an automatic post-tsunami flood-extent modelling concept using RapidEye multispectral satellite data and ASTER Global Digital Elevation Model Version 2 (GDEM V2) data of the eastern coast of Japan (captured after the Tohoku earthquake). In this paper, the authors developed both a bathtub-modelling approach and a cost-distance approach, and integrated the roughness parameters of different land-use types to increase the accuracy of flood-extent modelling. Overall, the accuracy of the developed models reached 87–92%, depending on the analysed test site. The flood-modelling approach was explained and results were compared with published approaches. We came to the conclusion that the cost-factor-based approach reaches accuracy comparable to published results from hydrological modelling. However the proposed cost-factor approach is based on a much simpler dataset, which is available globally.     

Multi—beam Sonar and Side—scan Sonar Image Co—registering and Fusing

Multi-beam Sonar and Side-scan Sonar compensate each other.In order to fully utilize all information,it is necessary to fuse two kinds of image and data.And the image co-registration is an important and complicated job before fusion.This paper suggests combining bathymetric data with intensity image,obtaining the characteristic points through the minimal angles of lines,and then deciding the corresponding image points by the maximal correlate coefficient in searching space.Finally,the second order polynomial is applied to the deformation model.After the images have been co-registered,Wavelet is used to fuse the images.it is shown that this algorthm can be used in the flat seafloor or the isotropic seabed.Verification is made in the paper with the observed data.     

多源遥感影像融合及其关键技术探讨

简述了多源遥感影像融合过程、三种融合层次及其优缺点；具体描述了常用的八种融合方法；根据近来多源遥感影像融合研究状况，提出了融合中需进一步研究的关键技术。     

下庄铀矿田控矿因素光-能谱融合图像解译应用研究

通过光-能谱融合图像处理、解译与部分野外验证,对下庄铀矿田发育的钾化蚀变带和低钍补体进行了识别与提取,指出铀成矿与钾化蚀变断裂带及低钍补体具有密切的成因与空间联系。另外,以能谱图像上发现的环状影像为线索,通过对岩体主体固结成岩后穹状构造隆升事件的研究,认为本区曾存在地幔柱,地幔柱作用引发了多种地质事件(或作用),这是形成铀矿田的根本原因所在